Spectrophotometer optical system based on Offner structure

Abstract

The invention relates to a spectrophotometer optical system based on an Offner structure, and the system comprises a first convergence part which is composed of a first lens and a second lens, an entrance slit, a concave reflector, a convex reflection grating, an exit slit, a collimating lens, and a beam splitter. The first convergence part is composed of a first lens and a second lens, the reference cell is composed of a plane mirror, the second convergence part is composed of a third lens and a fourth lens, and the third convergence part is composed of a fifth lens and a sixth lens. The spectrophotometer optical system can realize material optical analysis or test in a wide spectral range, and has the advantages of eliminating systematic errors such as light source fluctuation, environment temperature change, solvent absorption and the like, improving the data reliability, synchronously compensating a reference light path when the light source intensity is attenuated or fluctuated along with time, and improving the measurement accuracy. And the problem that a single-beam instrument needs to be calibrated frequently is avoided.

Description

Technical Field

[0001] The invention relates to an optical lens system, in particular to an Offner structure-based spectrophotometer optical system. Background Art

[0002] As modern industry's requirements for precision detection and quality control continue to increase, spectrophotometers are increasingly used in printing, semiconductor manufacturing, biomedical analysis and other fields. In the prior art, the core component of the spectrophotometer, the monochromator, usually adopts the Czerny-Turner spectrometer structure, which also has some shortcomings and problems, such as limited spectral range, insufficient imaging quality optimization, etc.; due to the complexity of the components, it is often expensive; bulky; and some spectrometers are difficult to maintain high detection efficiency and system stability during long-term or high-frequency use. Summary of the invention

[0003] In response to the above technical problems, the present invention proposes a spectrophotometer optical system based on the Offner structure, which can eliminate systematic errors such as light source fluctuations, ambient temperature changes, solvent absorption, etc. by adopting dual-light path synchronous measurement, thereby improving data reliability. When the light source intensity decays or fluctuates over time, the reference light path synchronously compensates, avoiding the problem of frequent calibration of single-beam instruments.

[0004] The present invention specifically relates to an Offner structure-based spectrophotometer optical system, comprising: a first converging portion (1) composed of a first lens (101) and a second lens (102) arranged in sequence along an optical path, an incident slit (2), a concave reflector (3), a convex reflective grating (4), an exit slit (5), a collimating lens (6), a beam splitter (7), a reference cell (8), a plane reflector (9), a second converging portion (1001) composed of a third lens (1002) and a fourth lens (1003), and a second converging portion (1002) composed of a third lens (1001) and a fourth lens (1003). A converging portion (10), a sample pool (11), and a third converging portion (12) composed of a fifth lens (1201) and a sixth lens (1202); wherein the optical axis (30) of the concave reflector is parallel to the incident light axis, the convex reflection grating (4) is coaxial with the concave reflector (3), and the concave reflector (3) and the convex reflection grating (4) form an offner structure; the first lens (101), the second lens (102), and the third lens (10 01) and the fourth lens (1002), the fifth lens (1201) and the sixth lens (1202) are all spherical mirrors; the incident light beam enters the first converging portion (1), is converged by the first lens (101) and the second lens (102) in sequence, passes through the path defined by the incident slit (2), is reflected by the concave reflector (3) to the convex reflective grating (4), is then split and reflected by the convex reflective grating (4) to the concave reflector (3), and is then reflected by the The concave reflector (3) reflects again to form a spectrum, and projects it onto the exit slit (5). The exit light beam is collimated by the collimating lens (6), and then split by the beam splitter (7), and passes through the reference cell (8) and the sample cell (11) respectively. The reference light path is then turned by the plane reflector (9), and finally the two paths of light are respectively converged and detected by the second converging part (10) and the third converging part (12). The optical focal length of the first lens (101) is Φ 101 , the focal power of the second lens (102) is Φ 102 , satisfying the following relationship: 0.1≤Φ 101 =Φ 102 ≤0.25, optical power Φ of the spectrophotometer optical system, optical power Φ of the first converging part 1 Satisfy 0.2≤Φ 1 / Φ≤0.3.

[0005] Furthermore, the distance from the incident slit (2) to the image plane of the second lens (102) is D 12 , the distance from the incident slit (2) to the concave reflecting mirror (3) is D 23 , the distance from the incident slit (2) to the convex reflection grating (4) is D 24， The curvature radius of the concave reflector (3) is R1 The curvature radius of the convex reflection grating (4) is R 2 , satisfying the following relationship: 0.2≤D 12 / D 23 ≤0.5, 0.4≤D 12 / D 24 ≤0.8,0.5≤|R 1 | / |R 2 |≤0.75.

[0006] Furthermore, the curvature radius of the concave reflector is R 1 , satisfying the following relationship: -0.02≤R 1 ≤-0.01.

[0007] Furthermore, the curvature radius of the convex reflection grating is R 2 , satisfying the following relationship: -0.04≤R 2 ≤-0.02.

[0008] Furthermore, the grating constant of the convex reflection grating is d, which satisfies the following relationship: 2μm≤d≤10μm.

[0009] Furthermore, the focal length Φ of the collimating lens (6) is 6 Satisfy 0.05≤Φ 6 ≤0.1, and the focal length of the spectrophotometer optical system Φ satisfies 0.1≤Φ 6 / Φ≤0.15.

[0010] Furthermore, the beam splitter (7) is coated with a semi-transmissive and semi-reflective film, and the transmission and reflection ratio is 50%:50%.

[0011] Furthermore, the focal power Φ of the third lens (1001) in the second converging portion (10) is 1001 The optical power Φ of the fourth lens (1002) 1002 Satisfy 0.1≤Φ 1001 =Φ 1002 ≤0.25, and the focal power Φ of the second converging portion (10) 10 And the focal power Φ of the spectrophotometer optical system satisfies 0.2≤Φ 10 / Φ≤0.3.

[0012] Furthermore, the optical power Φ of the fifth lens (1201) in the third converging portion (12) is 1201 The optical power Φ of the sixth lens (1202) 1202 Satisfy 0.1≤Φ 1201 =Φ 1202 ≤0.25, and the focal power Φ of the third converging portion (12) 12And the focal power Φ of the spectrophotometer optical system satisfies 0.2≤Φ 12 / Φ≤0.3.

[0013] The spectrophotometer optical system provided by the present invention is based on the offner structure, and has a high system stability after optimizing the component design; by adopting dual-light path synchronous measurement, systematic errors such as light source fluctuation, ambient temperature change, solvent absorption, etc. can be eliminated, and data reliability can be improved. When the light source intensity decays or fluctuates over time, the reference light path synchronously compensates, avoiding the problem of frequent calibration of single-beam instruments.

[0014] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0016] Figure 1 The structure and optical path schematic diagram of the optical system of a spectrophotometer according to an embodiment of the present invention are shown;

[0017] Figure 2 A schematic diagram showing a display of a diffuse spot corresponding to an optical system of a spectrophotometer according to an embodiment of the present invention is shown;

[0018] Figure 3 A schematic diagram of a curve of a modulation transfer function corresponding to an optical system of a spectrophotometer according to an embodiment of the present invention is shown.

[0019] Figure markings: 1-first converging section, 101-first lens, 102-second lens, 2-incident slit, 3-concave reflector, 30-optical axis of concave reflector, 4-convex reflection grating, 5-exit slit, 6-collimating lens, 7-beam splitter, 8-reference cell, 9-plane reflector, 10-second converging section, 1001-third lens, 1002-fourth lens, 11-sample cell, 12-third converging section, 1201-fifth lens, 1202-sixth lens. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below in conjunction with the accompanying drawings: the described embodiments are only part of the embodiments of the present invention, not all of them. The following embodiments are only for more clearly illustrating the technical solutions of the present invention and cannot be used to limit the scope of protection of the present invention.

[0021] It should be noted that in the present invention, the unit of optical focal length is mm, the unit of radius of curvature is mm, and the unit of eccentricity is mm.

[0022] In the embodiment disclosed in the present invention, in the order of the optical path, the spectrophotometer optical system based on the Offner structure includes: a first converging portion 1 composed of a first lens 101 and a second lens 102 arranged in sequence along the optical path, an incident slit 2, a concave reflector 3, a convex reflection grating 4, an exit slit 5, a collimating lens 6, a beam splitter 7, a reference cell 8, a plane reflector 9, a second converging portion 10 composed of a third lens 1001 and a fourth lens 1002, a sample cell 11 and a third converging portion 12 composed of a fifth lens 1201 and a sixth lens 1202.

[0023] The first converging portion 1 is capable of converging an incident light beam; an incident slit 2 is arranged on the converging side of the first converging portion 1, and the incident slit 2 is located on the extension line of the incident light axis, which is capable of limiting the path of the incident light beam, ensuring that the light beam can accurately enter the subsequent part of the optical system, and reducing optical path deviation and stray light interference; a concave reflector 3 is arranged toward the incident slit 2, and is capable of reflecting the incident light beam; a convex reflection grating 4 is arranged toward the concave reflector 3, and is capable of separating the incident light beam and reflecting it back to the concave reflector 3; a detection portion 5 is arranged toward the concave reflector 3, and is capable of receiving light signals and forming images.

[0024] The incident light beam enters the first converging part 1, is converged by the first lens 101 and the second lens 102 in sequence, is reflected by the concave reflector 3 to the convex reflector 4 after the path is limited by the incident slit 2, and then is split and reflected by the convex reflector 4 to the concave reflector 3, and then is reflected again by the concave reflector 3 to form a spectrum and projected onto the exit slit 5. The exiting light beam is collimated by the collimating lens 6, and then split by the beam splitter 7, and passes through the reference cell 8 and the sample cell 11 respectively. The reference light path is then turned by the plane reflector 9, and finally passes through the second converging part 10 and the third converging part 12 to converge the two paths of light for detection.

[0025] For the description of the first converging portion 1, the incident slit 2, the exit slit 5, the second converging portion 10 and the second converging portion 12, please refer to Figure 1 The direction of light in the spectrum. The above-mentioned "direction" means "there may be an optical path connection" but is not equivalent to "directly facing". The combined design of the concave reflector 3 and the convex reflection grating 4 reduces the aberration and optical path interference in the system through optical optimization, thereby improving the imaging quality and enabling the detection unit to obtain high-precision spectral imaging. The spectrophotometer optical system can cover a wide spectral range (200nm-1100nm) from ultraviolet to visible light and near-infrared regions, and has high resolution and good imaging quality.

[0026] In one embodiment, the optical axis of the concave reflector 3 is parallel to the incident light axis, the convex reflective grating 4 is coaxial with the concave reflector 3, and the concave reflector 3 and the convex reflective grating 4 form an offner structure; the first lens 101, the second lens 102, the third lens 1001 and the fourth lens 1002, the fifth lens 1201 and the sixth lens 1202 are all spherical lenses.

[0027] In a preferred embodiment, Figure 1 As shown, the optical power of the first lens 101 is Φ 101 , the focal length of the second lens 102 is Φ 102 , satisfying the following relationship: 0.1≤Φ 101 =Φ 102 ≤0.25, optical power Φ of the spectrophotometer optical system, optical power Φ of the first converging part 1 Satisfy 0.2≤Φ 1 / Φ≤0.3.

[0028] In a preferred embodiment, if Figure 1 As shown, the distance from the incident slit 2 to the image plane of the second lens 102 is D 12 , the distance from the incident slit 2 to the concave reflector 3 is D 23 , the distance from the incident slit 2 to the convex reflection grating 4 is D 24 , the curvature radius of the concave reflector 3 is R 1 , the curvature radius of the convex reflection grating 4 is R 2 , satisfying the following relationship: 0.2≤D 12 / D 23 ≤0.5, 0.1≤D 12 / D 24 ≤0.25,0.5≤|R 1 | / |R 2 |≤0.75.

[0029] The present invention uses a lens combination of two lenses as the first converging portion 1, the second converging portion 10 and the third converging portion 12, which can better bear the optical focal length, reduce the sensitivity of lens processing, and help eliminate aberrations.

[0030] In a preferred embodiment, Figure 1 As shown, the curvature radius of the concave reflector 3 is R 1 , satisfying the following relationship: 0.01≤R 1 ≤0.02.

[0031] In a preferred embodiment, if Figure 1 As shown, the curvature radius of the convex reflection grating 4 is R 2 , satisfying the following relationship: -0.04≤R 2≤-0.02.

[0032] In a preferred embodiment, if Figure 1 As shown, the grating constant of the convex reflection grating 4 is d, which satisfies the following relationship: 2μm≤d≤10μm.

[0033] In a preferred embodiment, if Figure 1 As shown, the convex reflective grating 4 is a blazed grating, and the blazing wavelength λ of the blazed grating satisfies 450nm≤λ≤550nm, which improves the splitting efficiency and wavelength resolution, so that the spectral detection range can cover a wide wavelength range of 200nm-1100nm.

[0034] In a preferred embodiment, if Figure 1 As shown, the focal length of the collimating lens 6 is Φ 6 Satisfy 0.05≤Φ 6 ≤0.1, and the focal length of the spectrophotometer optical system Φ satisfies 0.1≤Φ 6 / Φ≤0.15.

[0035] In a preferred embodiment, the beam splitter 7 is coated with a semi-transmissive and semi-reflective film, and the transmission and reflection ratio is 50%:50%.

[0036] In a preferred embodiment, if Figure 1 As shown, the focal length Φ of the third lens 1001 in the second converging portion 10 is 1001 The optical power Φ of the fourth lens 1002 is 1002 Satisfy 0.1≤Φ 1001 =Φ 1002 ≤0.25, and the focal power Φ of the second converging portion 10 10 And the focal power Φ of the spectrophotometer optical system satisfies 0.2≤Φ 10 / Φ≤0.3.

[0037] In a preferred embodiment, if Figure 1 As shown, the optical power Φ of the fifth lens 1201 in the third converging portion 12 1201 The focal power Φ of the sixth lens 1202 is 1202 Satisfy 0.1≤Φ 1201 =Φ 1202 ≤0.25, and the focal power Φ of the third converging portion 12 12 And the focal power Φ of the spectrophotometer optical system satisfies 0.2≤Φ 12 / Φ≤0.3.

[0038] In a preferred embodiment, the distance between the convex reflection grating 4 and the concave reflection mirror 3 is D 34 , the distance from the exit slit 5 to the concave reflector 3 is D 35 , satisfying the following relationship: D23 / D 34 ≥2, D 35 / D 34 ≥2; More preferably, the following relationship is satisfied: 0.9≤D 23 / D 35 ≤1.1. It should be noted that the use of convex grating and concentric optical design can reduce aberrations. The high line density and uniform dispersion characteristics of the convex grating ensure accurate focusing of different wavelengths, reduce spectral line broadening, and thus improve resolution.

[0039] Distance and length are defined in the direction parallel to the incident light axis, while height is defined in the direction parallel to the incident light axis. Figure 1 The above arrangement helps the optical system of the spectrophotometer to keep the diffuse spots of each color light focused.

[0040] A specific embodiment of the present invention and its performance effects are provided below for auxiliary explanation:

[0041] See also Figure 1 In the spectrophotometer optical system, the first converging part 1 is composed of a first lens 101 and a second lens 102 along the incident light axis. The focal length of the first lens 101 is Φ 101 is 0.15, and the focal length Φ of the second lens 102 102 is 0.15; the length (along the direction of the incident light axis) of the entire converging portion 1 (including the first lens 101, the second lens 102, and the assembly for fixing the first lens 101 and the second lens 102) is 48 mm. This design reduces the aberration of the system and achieves a lighter total weight than using a single-piece converging lens.

[0042] The converging portion 1 is connected to the incident slit 2 by a shading component. The body of the incident slit 2 intersects with the extended line of the incident light axis, and a slit is provided thereon that intersects with and is perpendicular to the extended line of the incident light axis, so that only the light converged by the converging portion 1 is allowed to pass through. The length of the slit is 2.2 mm and the width is 0.3 mm, so as to accommodate the light in the wavelength range of 200 nm-1100 nm that passes through after being converged by the converging portion 1.

[0043] The concave reflector 3 improves the correction capability of the system's off-axis aberrations, and only a single concave reflector 3 provides secondary reflection for the incident light. The mechanical degree of freedom of the system is reduced, which not only improves the compactness of the system, but also reduces the probability of damage during use. Its curvature radius is -0.01, the optical axis 30 of the concave reflector is parallel to the incident light axis, and the distance from its center of curvature to the incident slit 2 (along the direction of the incident light axis) is 22 mm.

[0044] The radius of curvature of the convex reflection grating 4 is -0.02, and its grating constant is 6μm. The optical axis coincides with the optical axis of the concave reflector, ensuring that the size of the concave reflector 3 can be as small as possible; its center of curvature relative to the concave reflector 3 is located on the same side as the concave reflector 3 to further eliminate aberrations; its blazing wavelength is 500nm, and the lateral distance (i.e., the direction parallel to the incident light axis) between the grating center and the curvature center of the concave reflector 3 is 26mm.

[0045] The exit slit 5 is located on the other side of the incident slit 2 relative to the convex reflection grating 4, and the lateral distance from the curvature center of the concave reflector 3 is 21 mm. A slit is provided thereon, which intersects with and is perpendicular to the extended line of the incident light axis, and only allows the light reflected by the concave reflector 3 to pass through. The length of the slit is 4.5 mm and the width is 0.1 mm, so as to accommodate the light in the wavelength range of 200 nm-1100 nm.

[0046] The focal power of the collimating lens 6 is Φ 1 The optical axis of the light source coincides with the optical axis of the exit slit 5, and the light emitted from the exit slit 5 is collimated to facilitate the subsequent beam splitting by the beam splitter 7.

[0047] The beam splitter 7, which is located on the same output optical axis as the output slit 5 and the collimating lens 6, splits the output light into two beams, which respectively pass through the reference cell 8 and the sample cell 11. Splitting the output light into two beams by the beam splitter 7 and performing synchronous detection separately can eliminate systematic errors such as light source fluctuation, ambient temperature change, solvent absorption, etc., and improve data reliability.

[0048] The reference cell 8 can be filled with a blank solution (solvent or reference substance). When the light source intensity decays or fluctuates over time, synchronous compensation can be performed by setting a reference light path to avoid the problem of frequent calibration of single-beam instruments, and can further eliminate systematic errors such as light source fluctuations, ambient temperature changes, solvent absorption, etc., thereby improving data reliability.

[0049] The plane reflecting mirror 9 converts the outgoing light passing through the reference cell 8 into output light perpendicular to the outgoing optical axis.

[0050] The second converging portion 10 is composed of a third lens 1001 and a fourth lens 1002. The focal length of the third lens 1001 is Φ 1001 is 0.12, and the focal length Φ of the fourth lens 1002 is 1002 is 0.12, and the length (along the direction of the incident optical axis) of the entire second converging portion 10 (including the third lens 1001 and the fourth lens 1002 and a component for fixing and connecting the third lens 1001 and the fourth lens 1002) is 20 mm.

[0051] The sample pool 11 is loaded with the sample to be tested.

[0052] The third converging portion 12 is composed of a fifth lens 1201 and a sixth lens 1202. The optical power of the fifth lens 1201 is Φ 1201 is 0.12, and the focal length Φ of the sixth lens 1202 is 1202 is 0.12, and the length (along the direction of the incident optical axis) of the entire third converging portion 12 (including the fifth lens 1201 and the sixth lens 1202 and a component for fixing and connecting the fifth lens 1201 and the sixth lens 1202) is 20 mm.

[0053] The imaging effect of this specific embodiment can be seen in Figure 2 , Figure 2 The figure shows the diffuse spots corresponding to the optical system of the spectrophotometer in this embodiment: at different lateral positions of the object plane (0mm, ±3mm, ±5mm) and corresponding image plane positions, light spots with wavelengths of 200nm (ultraviolet), 425nm (approximately blue light), 650nm (approximately red light), 875nm (near infrared), and 1100nm (near infrared) are gathered and imaged from bottom to top at the corresponding image plane according to the wavelength. In the lateral scale, the distribution of each light spot is relatively concentrated, and the distribution of the light spots of each wavelength on the image plane is concentrated in the middle part of the image; the position and size of the diffuse spots vary slightly at different angles, but there is no obvious diffusion; from short wave to long wave, the distribution of the diffuse spots is highly concentrated; it shows that the optical system of the spectrophotometer has high imaging accuracy for light of different wavelengths, good aberration control effect, high imaging stability, and good imaging quality in a wide spectrum range.

[0054] Figure 3 The schematic diagram of the curve of the modulation transfer function of the optical system of the spectrophotometer of the present invention is shown. The dotted dashed line at the top of the figure and close to the straight line represents the diffraction limit, which is the theoretical maximum resolution capability of the lens assembly. The other curves are schematic diagrams of the curve of the modulation transfer function of the optical system of the spectrophotometer of the present invention at multiple field angles. It can be seen that the curves of these modulation transfer functions are all close to the diffraction limit, and the closer to the diffraction limit, the higher the resolution capability of the lens. It can be seen from the figure that the MTF of the optical system of the spectrophotometer proposed by the present invention at the spatial frequency of 120lp / mm in the full field of view is greater than 0.3, and has excellent resolution capability.

[0055] Therefore, the spectrophotometer optical system of the embodiment of the present invention realizes synchronous measurement through dual optical paths, wherein the reference optical path passes through the blank solution, the sample optical path passes through the sample to be measured, and the two beams of light of the reference optical path and the sample optical path arrive at the detector alternately or synchronously. If there are errors such as light source fluctuation, ambient temperature change, solvent absorption, etc. in the optical path, the dual optical paths can calculate the absorbance A=-log10(I sample / I reference) in real time through the formula, so the errors can be offset by the ratio (I sample / I reference), thereby improving data reliability. In addition, the optical system can realize miniaturization and high-quality imaging in the spectral range of 200nm-1100nm, that is, simultaneously for the 200nm-380nm ultraviolet spectral region, the 380nm-780nm visible light spectral region, and the 780nm-1100nm near-infrared spectral region.

[0056] Although the specific values ​​of various parameters are shown in the above embodiment, it should be pointed out that various parts in the optical system of the spectrophotometer are electrically connected to the controller, and their angles and distances can be fine-tuned to meet the imaging requirements of different object distances; the performance parameters of each optical unit can also be adjusted within the range shown in the present invention, and the approximate Figure 2 That is, the above non-interval-limited specific parameters are only examples and do not limit the protection scope of the present invention.

[0057] It should be emphasized that the embodiments described in the present invention are illustrative rather than restrictive, and therefore the present invention is not limited to the embodiments described in the specific implementation manners, and any other implementation manners derived by those skilled in the art based on the technical solutions of the present invention also fall within the scope of protection of the present invention.

Claims

1. A spectrophotometer optical system based on Offner structure, characterized in that: The spectrophotometer optical system comprises: A first converging portion (1) composed of a first lens (101) and a second lens (102) arranged in sequence along an optical path, an incident slit (2), a concave reflection mirror (3), a convex reflection grating (4), an exit slit (5), a collimating lens (6), a beam splitter (7), a reference cell (8), a plane reflection mirror (9), a second converging portion (10) composed of a third lens (1001) and a fourth lens (1002), a sample cell (11), and a third converging portion (12) composed of a fifth lens (1201) and a sixth lens (1202); The optical axis (30) of the concave reflector is parallel to the incident light axis, the convex reflective grating (4) is coaxial with the concave reflector (3), and the concave reflector (3) and the convex reflective grating (4) form an offner structure; the first lens (101), the second lens (102), the third lens (1001), the fourth lens (1002), the fifth lens (1201), and the sixth lens (1202) are all spherical lenses; An incident light beam enters the first converging portion (1), is converged by the first lens (101) and the second lens (102) in sequence, passes through a path defined by the incident slit (2), is reflected by the concave reflector (3) to the convex reflective grating (4), is split by the convex reflective grating (4) and is reflected by the concave reflector (3) to form a spectrum, and is projected onto the exit slit (5). The exit light beam is collimated by the collimating lens (6), is split by the beam splitter (7), passes through a reference cell (8) and a sample cell (11), respectively, and the reference light path is deflected by the plane reflector (9). Finally, the two light paths are converged and detected by the second converging portion (10) and the third converging portion (12). The focal power of the first lens (101) is Φ 101 , the focal power of the second lens (102) is Φ 102 , satisfying the following relationship: 0.1≤Φ 101 =Φ 102 ≤0.25, the focal power Φ of the spectrophotometer optical system, the focal power Φ1 of the first converging part satisfies 0.2≤Φ 1 / Φ≤0.

3.

2. The spectrophotometer optical system according to claim 1, wherein: The distance between the incident slit (2) and the image plane of the second lens (102) is D 12 , the distance from the incident slit (2) to the concave reflecting mirror (3) is D 23 , the distance from the incident slit (2) to the convex reflection grating (4) is D 24， The curvature radius of the concave reflector (3) is R1, and the curvature radius of the convex reflective grating (4) is R2, satisfying the following relationship: 0.2≤D 12 / D 23 ≤0.5, 0.4≤D 12 / D 24 ≤0.8, 0.5≤|R1| / |R2|≤0.

75.

3. The spectrophotometer optical system according to claim 1, wherein: The curvature radius of the concave reflecting mirror (3) is R1, which satisfies the following relationship: -0.02≤R1≤-0.

01.

4. The spectrophotometer optical system according to claim 1, wherein: The curvature radius of the convex reflection grating (4) is R2, which satisfies the following relationship: -0.04≤R2≤-0.

02.

5. The spectrophotometer optical system according to claim 1, wherein: The grating constant of the convex reflection grating (4) is d, which satisfies the following relationship: 2μm≤d≤10μm.

6. The spectrophotometer optical system according to claim 1, wherein: The focal power Φ6 of the collimating lens (6) satisfies 0.05≤Φ6≤0.1, and the focal power Φ of the spectrophotometer optical system satisfies 0.1≤Φ6 / Φ≤0.

15.

7. The spectrophotometer optical system according to claim 1, wherein: The beam splitter (7) is plated with a semi-transmissive and semi-reflective film, and the transmission and reflection ratio is 50%:50%.

8. The spectrophotometer optical system according to any one of claims 1 to 7, characterized in that: The focal power Φ of the third lens (1001) in the second converging portion (10) is 101 The optical power Φ of the fourth lens (1002) 102 Satisfy 0.1≤Φ 1001 =Φ 1002 ≤0.25, and the focal power Φ of the second converging portion (10) 10 And the focal power Φ of the spectrophotometer optical system satisfies 0.2≤Φ 10 / Φ≤0.

3.

9. The spectrophotometer optical system according to claim 8, wherein: The optical power Φ of the fifth lens (1201) in the third converging portion (12) is 121 The optical power Φ of the sixth lens (1202) 122 Satisfy 0.1≤Φ 1201 =Φ 1202 ≤0.25, and the focal power Φ of the third converging portion (12) 12 And the focal power Φ of the spectrophotometer optical system satisfies 0.2≤Φ 12 / Φ≤0.3.

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